The present invention relates to a tire for motorcycles, and more particularly to a motorcycle tire having an improved steering stability with maintaining a rolling resistance performance and a drainage performance.
In recent years, a motorcycle tire having a reduced rolling resistance attracts attention in order to improve the fuel consumption performance in view of global environmental problems or the like. For example, JP 2009-298387 A proposes a motorcycle tire having a circumferential main groove extending continuously on the tire equator of a tread portion in the circumferential direction of the tire. In such a motorcycle tire, the rigidity in a central region of the tread portion is reduced to increase the ground contact width of the tire at the time of straight running, whereby the ground contact pressure is reduced to reduce the rolling resistance. Further, since such a circumferential groove extends continuously in the tire circumferential direction, a water film present between the tread surface and a road surface can be smoothly guided to enhance the drainage performance.
However, this motorcycle tire has a problem that the steering responsiveness is deteriorated in association with decrease in rigidity of the center region of the tread portion at the time of cornering at which a small camber angle is given and the center region mainly contacts the ground. Further, this motorcycle tire has a problem that the transition performance from straight running to cornering in which the ground contact surface shifts from the center region to an edge region located axially outward of the center region, is deteriorated, thus resulting in deterioration of the steering stability, since a rigidity difference between the center region and the edge region tends to become too large.
Accordingly, it is an object of the present invention to provide a tire for motorcycles capable of improving the steering stability with maintaining a good rolling resistance performance and a good drainage performance.
This and other objects of the present invention will become apparent from the description hereinafter.